chore: enhance Dockerfiles and package.json for improved build process

- Added ENV npm_config_ignore_scripts=true to frontend and backend Dockerfiles to skip scripts during npm install, optimizing build times.
- Introduced a postinstall script in package.json to ensure the build process for @mmapp/contracts runs after installation.

package.json

@@ -9,6 +9,7 @@
   "scripts": {
     "dev": "next dev",
     "build": "npm run build -w @mmapp/contracts && next build",
+    "postinstall": "npm run build -w @mmapp/contracts",
     "start": "next start",
     "lint": "eslint"
   },